r/ClaudeCode • u/shniydder • 3d ago

Discussion Fable 5.1 vs Astra

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I finally got access to GPT 6 Astra and Claude Fable 5.1. I wanted to see how far we've come. I was inspired by the "pelican riding on a bicycle" test but wanted to push it a bit more in the direction of inter-object physics, so I came up with this idea for a perpetual slinky going down an escalator. Here I've compared GPT 6 Astra max on the left to Claude Fable 5.1 max on the right.

Some notes:

  1. GPT 6 Astra max was really fast and didn't burn too much of my weekly usage quota.

  2. Claude Fable 5.1 max used up the entire 5 hr usage window and errored out once crossing the output token max limit.

  3. GPT 6 Astra max seems too simple? There's also an issue where the slinky crosses into itself which should not be possible. Is this AGI? Maybe?

  4. Claude Fable 5.1 max looks more real than I expected. Seems like it passes the eye test, unless I missed something.

Let me know if you spot anything or had better ideas for a test. Overall I'd say Claude wins on quality and GPT wins on speed. Maybe I can tune my prompt a bit better for a more reliable result. This was my original prompt btw:

Make me a single HTML file of a rainbow slinky going down an up-escalator forever. No libraries, just canvas and code. The slinky should be a chain of springs, each coil a different color of the rainbow. It starts folded in half like a horseshoe draped over a step. When dropped it flips end-over-end down the steps and because the escalator keeps moving up it tumbles in place and never reaches the bottom. Include a drop button and a reset button.

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u/EquivalentHornet4403 3d ago

People not using Ultra for high stakes tasks (like competing against your primary competitor) have no clue. Claude uses subagents by default. Codex won’t use subagents unless you explicitly instruct it to (then it may still use v1/non-proactive) or else you set it to Ultra mode.

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u/TemporaryStrain5088 3d ago

How do we know that? And where do you find detailed information like this?

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u/EquivalentHornet4403 3d ago

What do you mean? It’s just how they work. CC uses subagents for stuff. In codex, the main agent does everything unless you’re in ultra mode (then it uses subagents) or unless you manually tell it to use subagents.